This invention relates generally to eyeglasses or spectacles; more particularly it relates to eyeglasses having interchangeable lenses of the type that the owner can change or replace without the necessity of obtaining skilled assistance.
The concept of permitting owners of eyeglasses to change their own lenses is now established in many parts of the world. This concept has been embodied in eyeglasses that have been effectively marketed by companies such as Optyl Eyewear Fashion International Corporation under the "Carrera" trademark; they are made in accordance with the teachings of U.S. Pat. No. 4,176,921 to Matthias entitled "Eyeglasses Having Removable Lenses." The most popular usage of the Carrera-style eyeglasses is in the form of sunglasses and the like, wherein plain, mirrored or tinted lenses (e.g., smoke, green, yellow and grey) are selectively interchanged by the owner, depending upon lighting conditions and whatever activity the owner has in mind. However, this particular style of eyewear has one characteristic which at least some people find to be a liability, namely, a single latching mechanism is effective to unlatch both of the lenses simultaneously. The result is that a retaining mechanism in accordance with the Matthias patent could cause one lens to be accidentally dropped while the owner's attention is being focused on removing and replacing an adjacent lens.
Another construction for interchangeable lenses is illustrated in U.S. Pat. No. 4,504,127 to Cottet entitled "Frame Front For Eyeglasses Permitting Interchangeability Of Lenses". This patent does teach that each of two lenses ought to be capable of being individually removed from their respective sockets or cavities; but it is reported--in practice--that deflecting the main bridge member usually causes both lenses to fall out simultaneously. If these reports are valid, this may be an example of the widely recognized "truth" that the average consumer does not always read directions before trying to use a new product, nor does the average consumer possess the dexterity or faculties that design engineers do. So what may work nicely in the laboratory will not always work in the field--when amateurs get hold of something. But giving the Cottet device the benefit of any doubt, and assuming that it can be made to regularly and reliably release only one lens at a time, it does so at the expense of using a unique and unusually strong main bridge member; otherwise the bridge member would be subject to breaking after a disappointingly few changes of the lenses.
Another device of the prior art is shown in U.S. Pat. No. 4,523,819 to Dianitsch and Pschebezin entitled "Eyeglasses With Exchangeable Lenses." This device reportedly has the advantage of being usable with eyeglasses having only partial rims. However, it achieves its results with a latching mechanism which appears to be so sophisticated as to almost ensure that it could never be made with manufacturing techniques that are economical and adapted to ordinary mass production. So when a large manufacturer is searching for a reliable mechanism for use in meeting the world's needs for sunglasses and other eyeglasses having interchangeable lenses, it is likely that something more simple would be desired. It is an object of this invention to provide such a simple--but strong, attractive and dependable--device.
It is another object to provide an eyeglass mechanism in which both lenses may be selectively replaced by the owner--but only one at a time.
Another object is to provide a retaining mechanism which can be combined expeditiously with a wide variety of basic eyeglass frames, so that a manufacturer of eyeglasses need not be forced to create highly specialized and unique frames in order to employ a retaining mechanism for a pair of lenses.
Still another object is to provide a retaining mechanism which has a relatively short profile--in a vertical direction, and which can be placed at the top of an eyeglass frame without extending so far downward that the mechanism might interfere with the wearer's vision.
These and other objects will be apparent from a careful reading of the specification and the claims appended thereto, with appropriate reference to the drawings provided herewith.